Culture apparatus for microscope viewing of this type such as those described in Japanese Patent Laid-open (kokai) public disclosure 2008-259430 and shown in FIG. 8, are well known in the art. A culture apparatus for microscope viewing 100 shown in FIG. 8 comprises a housing unit 103 and a lid 107 for closing an upper opening of the housing unit. A water tank 105 is provided along the inner side wall of the housing unit 103. The interior space defined by the inner edge of the water tank 105 can accommodate a container such as a well plate W for holding culture media or medium A and a specimen or specimens B. The culture apparatus, which accommodates the well plate, are adapted to be rested on the stage of a microscope.
In order to hold the specimen B such as cells within the culture solution A under the conditions suitable for making observation, it is required to keep a temperature of the culture solution A stable at or around 37° C. In the prior art, a heater plate 109 of thin aluminum sheet of high thermal conductivity is provided over the lower opening of the housing unit 103 for heating the solution A within the well plate.
The heater plate 109 has a plurality of through holes 111 at positions corresponding to wells w of the well plate W for making the wells w remain for the microscope viewing.
Recently, there has been used an inverted microscope for high magnification observation. In order to make observation operation in high magnification, the objective lens R is likely to be close to the lower surface of the housing unit 103. Accordingly, if observation object is changed from one well to an adjacent well, as shown in arrow in the figure, the objective lens R is retracted from the one well, the housing unit 103 is moved in X-Y (two dimensional) directions on the on the microscope stage S in order that the objective lens S faces on the adjacent well, and the objective lens R is closed to the adjacent well, because the wells w is plated on the heater plate 109. This is a cumbersome operation. Even if such operation can be effected automatically, complicated programming is required. Further, if there is used as the well plate, a multi-type one (for example, 96 wells), it is difficult to bring the objective lens R even close to the lower surface of unit 103, because the hole web of the heater plate 108 is smaller.
So called oil or water immersion lens in which the space between the exposed lower surface of the container and the objective lens R is filled with oil or water, is used to observe the specimen B for clear observation in high magnification. However, the liquid ball made on the top of the objective lens R, which fills the space is apt to be broken under the effect of the reciprocal movement of the objective lens R.
On the other hand, when the heater plate 109, instead, has one large though hole, which cover all of the wells w and heats the wells s by w by transferring heat energy from the web of the heater plate 109, it is impossible to heat each well w equally, because of difference in distance between each well and the heater plate. In other words, the one wells w adjacent the web of the heater plate 108 is rich-heated, and the other wells w far away from the web thereof is poor-heated.